Halogen-containing organic materials stabilized with organotin phosphate esters



HALOGEN-CONTAINING ORGANIC MATERIALS STABIISJZED WITH ORGANOTINPHOSPHATE ESTER James M. Church, Tenafly, Hugh E. Ramsden, Metuchen, andHerbert Hirschland, Rahway, N. J., and Harry W. Buchanan, Larchmont, N.Y., assignors to Metal & Thermit Corporation, New York, N. Y., acorporation of New Jersey No Drawing. Original application May 21, 1949,Serial No. 94,746, now Patent No. 2,630,442, dated March 3, 1953.Divided and this application October 15, 1952, Serial No. 314,948

T 3 Claims. (Cl. 260-455 This invention relates to compositionsincorporating new organotin compounds comprising organotin phosphateesters in which the organotin portion is connected to the phosphategroup through tin and consists of two to three organic radicalsconnected to tin, and in which the ester portion connected to thephosphate group con sists of one to two organic radicals.

In one form, the organotin compounds may be represented generally by theformula: R1R2(SnR3R4R5)PO4, in which R3, R4 and R5 are organic radicalsselected from the group consisting of alkyl, aryl, aralkyl, heterocyclicand cycloaliphatic radicals, each of which is connected to tin, which inturn is connected to the phosphate group, and in which R1 and R2 areorganic radicals selected from the group consisting of alkyl, aryl,aralkyl, heterocyclic and cycioaliphatic radicals, each of which isconnected to the phosphate group. Under this definition, a radicalconnected to an oxygen atom of the phosphate group is to be understoodas being connected to the phosphate group. By alkyl and aryl" it isintended to include substituted as Well. as unsubstituted alkyl and arylgroups. As is evident, the compounds covered by the above formula belongto the class of simple phosphates. Another class of simple phosphatesmay be represented generally as: R1(SnR3R)PO4,' in which R1, R3 and R4have the values and linkages as above. The invention also contemplatesthe more complex polyphosphate esters which may be represented asfollows:

in which R1, R2, R3, R4, and R5 have the same values and linkages asbefore.

When the R1 and R2 roups in the above formulas are alkyl, it ispreferred that they contain at least four, and more preferably six toten carbon atoms. When the R3, R4 and R5 groups are alkyl, they maycontain up to sixteen carbons, preferably three to six. As alkylradicals there may be mentioned methyl, ethyl, propyl, butyl, isobutyl,amyl, isoamyl, hexyl, isohexyl, cyclohexyl, octyl, lauryl, etc.Substituted alkyls include alkyl groups substituted by halogen and othergroups. For R1 and R2, the alkyl groups may be the same or different,and similarly for R3, R4 and R5, the groups may be the same ordifierent. Withinthe class of aryl radicals such groups as phenyl,tolyl, xylyl, naphthyl, etc. are useful, as are aralkyl radicals likebenzyl, phenethyl, and substituted aryls like the halobenzenes, etc.

2,743,257 Patented Apr. 24, 1956 As specific examples of compounds,there may be mentioned:

Dioctyl, tributyl tin, phosphate (CaH1'z)2l[Sn(C4H9)a]PO4 Diphenyl,triphenyl tin, phosphate Ph2(SnPh3)PO4 Hexyl, dipropyl tin, phosphateCsH1a[Sn(CsH7)2]PO4 Didecyl, di-trihexyl tin, pyrophosphate (C10H21 2[Sn (CsHis 3] 2120:

Dihexyl diphenyl tin, pyrophosphate (CaHrs)a(SnPhz)P2O7 Dicapryl,tri-tributyl tin, triphosphate (C8H1'I)2[SII(C4H9)3]3P3010 Difuryl,tri-tributyl tin, triphosphate (C4HaO)z[Sn(C4H9)s]sPsO1o All of theabove and related compounds are intended to be included within the scopeof the invention, and within the classification which may be defined asorganotin phosphate esters, in which the inorganic conconstituents: tinand phosphorous, in combination with various organic radicals, arelinked together directly or through oxygen.

The organotin phosphate esters may be made by reacting an organotincompound with an acid phosphate ester, i. e., a phosphate estercontaining one or more alkyl, aryl, aralkyl, heterocyclic andcycl'oaliphatic radicals substituted therein. Examples of such phosphateesters are dioctyl acid phosphate, phenyl dihydrogen phosphate, octylfuryl dihydrogen pyrophosphate, cyclohexyl octyl hydrogen phosphate,dibenzyl dihydr-ogen pyrophosphate, etc. Organotin compounds includedialkyl tin oxides like dibutyl tin oxide, dipropyl tin oxide, diamyltin oxide, didecyl tin oxide; diaryl tin oxides like diphenyl tin oxide,ditolyl tin oxide, dixylyl tin oxide, dinaphthyl tin oxide; diaralkyltin oxides like dibenzyl tin oxide, diphenethyl tin oxide; also difuryltin oxide, dithienyl tin oxide, dicyclohexyl tin oxide; also trialkyltin hydroxides like tributyl tin hydroxide, tripropyl tin hydroxide,trihcxyl tin hydroxide; triaryl tin hydroxides like triphenyl tinhydroxide; triaralkyl tin hydroxides like tribenzyl tin hydroxide; alsotrifuryl tin hydroxide, tri-beta-pyridyl tin hydroxide; also dialkyl,diaryl, and diaralkyl tin dihalides, and trialkyl, triaryl, andtriaralkyl tin monohalides, such as dibutyl tin dichloride, diamyl tindichloride, dihexyl tin dichloride, dioctyl tin dichloride, didecyl tindichloride, diphenyl tin dichloride, dibenzyl tin dichloride, tributyltin chloride, triphenyl tin chloride, tribenzyl tin chloride; alsodicyclohexyl tin dichloride, difuryl tin dichloride, tri-beta-pyridyltin bromide, tri-beta-quinolyl tin bromide, trimethylcyclohexyl tinbromide, etc.

In the case of the organotin halides, the reaction may also be performedby using an alkali salt of the acid phosphate ester. This is thepreferred method for preparing the organotin phosphate esters. Asexamples of such salts, there may be mentioned disodium buitylphosphate, mono potassium dicapryl phosphate, sodium trihexylpyrophosphate, etc. The reaction may be carried out by bringing togetherthe organotin halide and the alkali salt of the acid phosphate, ester inany generally suitable proportions, although for practical reasons alarge excess of one reactant isto be avoided. Satisfactory results maybe obtained by using stoichiometrical quantities of the reactants. It ispreferable to conduct the reaction at temperatures ranging from about 50to about C. If a solvent is used, as is desirable, it is advantageous torun the reaction at the boiling point of the solvent, keeping within theabove temperature range. Solvents like alcohol, alcohol-water, ether,hexane, heptane, carbon tetrachloride, toluene, etc. are suitable. Thereaction may also proceed at room temperatures, although at a reducedrate. At higher temperatures, the reaction may require up to one or twohours for substantial completion. The pressure during the reaction isatmospheric, although it is possible to carry it out under higher orlower pressures.

When the organotin compound is reacted with an acid phosphate ester, thereaction conditions may be substantially as just described, although inthis case a longer time may be required.

Alternatively, the organotin phosphate esters may be made byreacting'anorganotin compound of the kind described with a phosphoric acid or aderivative of the same and with an esterifying agent. All three of thesereactants may be brought together at the same time and reacted, or elsethe first two may be reacted separately andthe product thereofsubsequently esterified. Reaction conditions substantially as justdescribed will prevail. As phosphoric acids, there may be mentioned theortho-, pyro-, meta-, and poly-acids; and as derivatives of phosphoricacids the following are useful; phosphorus pentoxide, phosphorusoxychlorides, phosphorus pentachloride. Esterifying agents or reactantsinclude straight and branched chain and cyclic alcohols and olefins, andalkyl, aryl and aralkyl halides, suitably chosen to provide alkyl, aryl,or aralkyl radicals of the kind described above in connection with thealkali salts of the acid phosphate esters.

Examples 1 to 3 may illustrate the preparation of several compounds byvarious methods. The compound underlined at the beginning of eachexample is the product of the method described therein.

EXAMPLE 1 v Dioctyl, tributyl tin, phosphate Approximately 26 g. ofoctyl alcohol (0.2M) is added to g. (0.1M) of phosphorus oxychloridedissolved in 100 cc. benzene and the mixture refluxed at 80-85 C. forone hour during which time hydrogen chloride is evolved. The hotreaction mixture is blown with air to rid it of the residual hydrogenchloride and a 10% sodium hydroxide solution added until the aqueousportion of the reaction mixture tests neutral to litmus. To the aqueoussolvent reaction mixture is added 33 g. (0.1M) of tributyl tinmonochloride dissolved in 100 cc. of benzene. The mixture is heated to agentle reflux for 6 to 10- hours for completion of the reaction asevidenced by the formation of a strong salt solution as the lower layer.The salt layer is separated and the upper oil layer washed several timeswith water. Finally the washed oil layer is stripped free of solvent bydistillation leaving a light straw yellow viscous oily residue, whichmay be distilled in vacno to produce a practically water whitedistillate.

EXAMPLE 2 Dicapryl, tri-tributyl tin, triphosphate Fiity-five grams. oftrisodium dicapryl triphosphate (0.1M) is dissolved in 100 cc. water and100 cc. ethyl alcohol. To this solution is added 98 g. 01' tributyl tinmonochloride (0.3M) dissolved in 100 cc. ethyl alcohol. The combinedmixture is heated gently for 10l2 hours and finally quenched with waterand the oil layer extracted with toluene. Upon removal of toluene fromthe separated organic layer, a very light yellow viscous oily liquid isobtained.

EXAMPLE 3 Dihexyl, diphenyl tin, pyrophosphate A mixture of 41 g. 'hexylalcohol (0.4M) and 28 g. phosphorus pentoxide (0.2M) are gently heatedtogether. To the resulting mass is slowly added dilute sodium hydroxideuntil the solution tests neutral to litmus. A separate solutioncontaining 68 g. diphenyl tin dichloride (0.2M) dissolved in cc. oftoluene is prepared and added to the above stirred phosphate solution,and the resulting mixture heated to a gentle reflux for 3 to 4 hours.The lower aqueous layer is decanted and the upper product layer washedseveral times with warm water. Upon removalof the toluene bydistillation under vacuo, a thick light yellow viscous oily liquid isobtained.

The organotin phosphate esters are suitable for use as stabilizers fororganic materials containing chlorine or other halogen, such as vinylresins which contain a polymerized vinyl halide, chlorinated paratlinscontaining from 10 to 40 carbon atoms per molecule, chlorinatedstearates, chlorinated biphenyls, DDT, chlorinated rubber, and otherpreferably high molecular weight halogenated material. As is known, suchmaterials are inherently unstable even under ordinary conditions ofnormal temperatures, humidities, and the presence of traces ofcontaminating agents. At the higher temperatures of processing orapplication their inherent instability is greatly aggravated, resultingin considerable decomposition of the materials and making them moresusceptible to attack by chemical agents, such as oxygen of the air.Consequently the properties of these halogenated substances are greatlychanged by deterioration and they sufier considerable loss of mechanicalstrength, solvent characteristics, fluid properties, resistance toaging, and other crictical properties. Because of their instability,they are readily discolored upon exposure to light or heat, renderingthem useless for the purpose for which they were intended. By addingfrom about 0.1 to about 10% of an organotin phosphate ester to thematerial to be stabilized, a composition is obtained which is greatlyimproved in stability by comparison with the unstabilized material. Thefollowing examples may illustrate the procedure for preparing suchcompositions.

EXAMPLE 4 To a resinous composition containing 62 parts by weight of apolyvinyl resin consisting of 87% vinyl chloride and 13% vinyl acetate,35 parts of dioctyl phthalate as. the plasticizer, add 3 parts ofdioctyl, tributyl tin, phosphate as stabilizer. This mixture may becompounded by mixing and fluxing for a few minutes while hot on adifferential speed roll mill at to C. and then removed from the mill asa plastic sheet. The composition is then ready to be molded.

EXAMPLE 5 To another resinous composition containing 60 parts of vinylresin (87% vinyl chloride and 13% vinyl acetate) and 38 parts of dihexylsebacate as the plasticizer, add 2 parts of dicapryl, tri-tributyl tin,triphosphate as stabilizer and compound as in the preceding example.

EXAMPLE 6 In this case a chlorinated parafiin may be stabilized. Add 4parts of didecyl, di-trihcxyl tin, pyrophosphate to 96 parts of achlorinated paraffin (42% chlorine).and mix in any desired manner.

The foregoing compositions may include additional ingredients such aspigments and fillers of the inorganic or organictype, solvents of agreat variety, dyestutis, etc. The stabilizing effect of the organotinphosphate esters is not limited to plasticizecl or solution mixtures asthey are etfective by merely bringing the stabilizer into contact withthe halogenated compound, regardless of their compatibility with othercomponents of the mixtures.

Although the invention has been described in connection with more orless specific embodiments, it will be understood that it is capable ofobvious variations without departing from its. scope.

This application is a division of copending: application Serial Number94,746, filed May 21, 1949, now Patent No. 2,630,442.

In the light of the foregoing description, is claimed:

1. A composition comprising an organic, halogen-containing materialhaving incorporated therein from about 0.1 to about by weight of anorganotin phosphate ester, said material being characterized by havingat least 10 carbon atoms per molecule, by being inherently unstable atnormal temperatures and normal humidities, and by exhibiting increasedinstability at higher temperatures, said material being selected fromthe class consisting of a halogen-containing vinyl resin, :1 chlorinatedparaffin containing 10 to 40 carbon atoms, a chlorinated stearate, achlorinated biphenyl, dichlorodiphenyltrichloroethane, and a chlorinatedrubber, said ester consisting of at least one organotin portionconnected to the phosphate group through tin, said portion consisting oftwo to three organic radicals connected to tin with said organicradicals being selected from the class consisting of alkyl and arylradicals, said alkyl radicals having up to 16 carbon atoms per radical,each said tin atom being connected to the phosphate group through atleast one oxygen atom of said group, said ester portion being connectedto the phosphate group and consisting of one to two organic radicalsselected from the class consisting of alkyl and aryl radicals, saidlast-mentioned alkyl radicals having at least 4 carbon atoms perradical, and each said organic radical of said ester portion beingconnected to the phosphate group through at least one oxygen atom ofsaid group.

2. A stable, chlorine-containing resin having incorporated therein fromabout 0.1 to about 10% by weight of an organotin phosphate ester, saidester consisting of at least one organotin portion connected to thephosphate group through tin, said portion consisting of two to threealkyl radicals connected to tin, each alkyl having up to 16 carbon atomsper radical, each said tin atom being connected to the phosphate groupthrough at least one oxygen atom of said group, said ester portion beingconnected to the phosphate group and consisting of one to two organicradicals selected from the class consisting of alkyl and aryl radicals,said last-mentioned alkyl radicals having at least 4 carbon atoms perradical, and each said organic radical of said ester portion beingconnected to the phosphate group through at least one oxygen atom ofsaid group.

3. A stable, chlorine-containing resin having incorporated therein fromabout 0.1 to about 10% by weight of an organotin phosphate ester, saidester consisting of at least one organotin portion connected to thephosphate group through tin, said portion consisting of two to threealkyl radicals connected to tin, each alkyl having up to 16 carbon atomsper radical, each said tin atom being connected to the phosphate groupthrough at least one oxygen atom of said group, said ester portion beingconnected to the phosphate group and consisting of one to two alkylradicals having at least 4 carbon atoms, each said alkyl radical of theester portion being connected to an oxygen atom of the phosphate group.

4. A stable, plasticized, vinyl resin composition comprising polymerizedvinyl halide, said resin having incorporated therein from about 0.1 toabout 10% by weight of an organotin phosphate ester, said esterconsisting of at least one organotin portion connected to the phosphategroup through tin, said portion consisting of two to three alkylradicals connected to tin, each alkyl having 3 to 6 carbon atoms perradical, each said tin atom being connected to the phosphate groupthrough at least one oxygen atom of said group, said ester portion beingconnected to the phosphate group and consisting of one to two alkylradicals having from 6 to 10 carbon atoms, each said alkyl radical ofthe ester portion being connected to an oxygen atom of the phosphategroup.

the following 5. A stable composition comprising a chlorinated paraflinhaving from 10 to 40 carbon atoms per molecule and having incorporatedtherein from about 0.1 to about 10% by weight of an organotin phosphateester, said ester consisting of at least one organotin portion connectedto the phosphate group through tin, said portion consisting of two tothree alkyl radicals connected to tin, each alkyl having 3 to 6 carbonatoms per radical, each said tin atom being connected to the phosphategroup through at least one oxygen atom of said group, said ester portionbeing connected to the phosphate group and consisting of one to twoalkyl radicals having from 6 to 10 carbon atoms, each said alkyl radicalof the ester portion being connected to an oxygen atom of the phosphategroup.

6. A stable, chlorine-containing resin having incorporated therein fromabout 0.1 to about 10% by Weight of an organotin phosphate ester, saidester consisting of at least one organotin portion connected to thephosphate group through tin, said portion consisting of two to threealkyl radicals connected to tin, each alkyl having up to 16 carbon atomsper radical, each tin atom being connected to the phosphate groupthrough at least one oxygen atom of said group, said ester portion beingconnected to the phosphate group and consisting of one to two arylradicals, each said aryl radical of the ester portion being connected toan oxygen atom of the phosphate group.

7. A composition comprising an organic, halogen-containing materialhaving incorporated therein from about 0.1 to about 10% by weight of anorganotin phosphate ester, said material being characterized by havingat least 10 carbon atoms per molecule, by being inherently unstable atnormal temperatures and normal humidities, and by exhibiting increasedinstability at higher temperatures, said material being selected fromthe class consisting of a halogen-containing vinyl resin, a chlorinatedparaflin containing 10 to 40 carbon atoms, a chlorinated stearate, achlorinated biphenyl, dichlorodiphenyltnichloroethane, and a chlorinatedrubber, said ester consisting of at least one organotin portionconnected to the phosphate group through tin, said portion consisting oftwo to three aryl radicals connected to tin, each said tin atom beingconnected to the phosphate group through at least one oxygen atom ofsaid group, said ester portion being connected to the phosphate groupand consisting of one to two aryl radicals, each said aryl radical ofthe ester portion being connected to an oxygen atom of the phosphategroup. i

8. A composition comprising an organic, halogen-containing materialhaving incorporated therein from about 0.1 to about 10% by weight of anorganotin phosphate ester, said material being characterized by havingat least 10 carbon atoms per molecule, by being inherently unstable atnormal temperatures and normal humidities, and by exhibiting increasedinstability at higher temperatures, said ester consisting of at leastone organotin portion connected to the phosphate group through tin, saidportion consisting of two to three organic radicals connected to tinwith said organic radicals being selected from the class consisting ofalkyl and aryl radicals, said alkyl radicals having up to 16 carbonatoms per radical, each said tin atom being connected to the phosphategroup through at least one oxygen atom of said group, said ester portionbeing connected to the phosphate group and consisting of one to twoorganic radicals selected from the class consisting of alkyl and arylradicals, said last-mentioned alkyl radicals having at least 4 carbonatoms per radical, and each said organic radical of said ester portionbeing connected to the phosphate group through at least one oxygen atomof said group.

No references cited.

1. A COMPOSITION COMPRISING AN ORGANIC, HALOGEN-CONTAINING MATERIALHAVING INCORPORATED THEREIN FROM ABOUT 0.1 TO ABOUT 10% BY WEIGHT OF ANORGANOTIN PHOSPHATE ESTER, SAID MATERIAL BEING CHARACTERIZED BY HAVINGAT LEAST 10 CARBON ATOMS PER MOLECULE, BY BEING INHERENTLY UNSTABLE ATNORMAL TEMPERATURES AND NORMAL HUMIDITIES, AND BY EXHIBITING INCREASEDINSTABILITY AT HIGHER TEMPERATURES, SAID MATERIAL BEING SELECTED FROMTHE CLASS CONSISTING OF A HALOGEN-CONTAINING VINYL RESIN, A CHLORINATEDPARAFFIN CONTAINING 10 TO 40 CARBON ATOMS, A CHLORINATED STERATE, ACHLORINATED BIPHENYL, DICHLORODIPHENYLTRICHLOROETHANE, AND A CHLORINATEDRUBBER, SAID ESTER CONSISTING OF AT LEAST ONE ORGANOTIN PORTIONCONNECTED TO THE PHOSPHATE GROUP THROUGH TIN, SAID PORTION CONSISTING OFTWO TO THREE ORGANIC RADICALS CONNECTED TO TIN WITH SAID ORGANICRADICALS BEING SELECTED FROM THE CLASS CONSISTING OF ALKYL AND ARYLRADICALS, SAID ALKYL RADICALS HAVING UP TO 16 CARBON ATOMS PER RADICAL,EACH SAID TIN ATOM BEING CONNECTED TO THE PHOSPHATE GROUP THROUGH ATLEAST ONE OXYGEN ATOM OF SAID GROUP, SAID ESTER PORTION BEING CONNECTEDTO THE PHOSPHATE GROUP AND CONSISTING OF ONE TO TWO ORGANIC RADICALSSELECTED FROM THE CLASS CONSISTING OF ALKYL AND ARYL RADICALS, SAIDLAST-MENTIONED ALKYL RADICALS HAVING AT LEAST 4 CARBON ATOMS PERRADICAL, AND EACH SAID ORGANIC RADICAL OF SAID ESTER PORTION BEINGCONNECTED TO THE PHOSPHATE GROUP THROUGH AT LEAST ONE OXYGEN ATOM OFSAID GROUP.